An Anthocyanin-Rich Mixed-Berry Intervention May Improve Insulin Sensitivity in a Randomized Trial of Overweight and Obese Adults.
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ABSTRACT:
SUBMITTER: Solverson PM
PROVIDER: S-EPMC6950395 | biostudies-literature | 2019 Nov
REPOSITORIES: biostudies-literature
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Project description:Dietary supplementation with whole blueberries in a preclinical study resulted in a reduction in glucose concentrations over time. We sought to evaluate the effect of daily dietary supplementation with bioactives from blueberries on whole-body insulin sensitivity in men and women. A double-blinded, randomized, and placebo-controlled clinical study design was used. After screening to resolve study eligibility, baseline (wk 0) insulin sensitivity was measured on 32 obese, nondiabetic, and insulin-resistant subjects using a high-dose hyperinsulinemic-euglycemic clamp (insulin infusion of 120 mU(861 pmol)?m(-2)?min(-1)). Serum inflammatory biomarkers and adiposity were measured at baseline. At the end of the study, insulin sensitivity, inflammatory biomarkers, and adiposity were reassessed. Participants were randomized to consume either a smoothie containing 22.5 g blueberry bioactives (blueberry group, n = 15) or a smoothie of equal nutritional value without added blueberry bioactives (placebo group, n = 17) twice daily for 6 wk. Both groups were instructed to maintain their body weight by reducing ad libitum intake by an amount equal to the energy intake of the smoothies. Participants' body weights were evaluated weekly and 3-d food records were collected at baseline, the middle, and end of the study. The mean change in insulin sensitivity improved more in the blueberry group (1.7 ± 0.5 mg?kg FFM(-1)?min(-1)) than in the placebo group (0.4 ± 0.4 mg?kg FFM(-1)?min(-1)) (P = 0.04). Insulin sensitivity was enhanced in the blueberry group at the end of the study without significant changes in adiposity, energy intake, and inflammatory biomarkers. In conclusion, daily dietary supplementation with bioactives from whole blueberries improved insulin sensitivity in obese, nondiabetic, and insulin-resistant participants.
| S-EPMC3139238 | biostudies-literature
Project description:Emerging research indicates that nuts are a source of health-promoting compounds demonstrating cardioprotective benefits. However, most studies have assessed the effect of single nuts rather than a nut mixture. The objective of this study was, therefore, to examine the effect of mixed-nut consumption on cardiovascular disease (CVD) risk factors in overweight and obese adults. In a randomized, parallel-arm, controlled trial, 48 participants consumed isocaloric (250 kcal) amounts of pretzels or mixed-nuts. Body weight (BW) (p = 0.024), BMI (p = 0.043), and insulin levels (p = 0.032) were significantly lower in the nut group compared to the pretzel group. Mixed-nut consumption also significantly reduced glucose (p = 0.04) and insulin (p = 0.032) levels after 4 and 8 weeks compared to baseline, respectively. Lactate dehydrogenase of the nut group was significantly lower than the pretzel group (p = 0.002). No significant differences were detected between groups for triglycerides, LDL-C, and HDL-C. However, pretzel consumption increased triglycerides (p = 0.048) from 4 weeks to 8 weeks. Moreover, LDL-C increased (p = 0.038) while HDL-C transiently decreased (p = 0.044) from baseline to 4 weeks. No significant lipid changes were detected within the nut group. Our results suggest that supplementing the diet with mixed-nuts could improve CVD risk factors by improving BW and glucose regulation in comparison to a common carbohydrate-rich snack without promoting the negative effects on lipids detected with pretzels.
| S-EPMC6683273 | biostudies-literature
Project description:Dietary fiber, an important regulator of intestinal microbiota, is a promising tool for preventing obesity and related metabolic disorders. However, the functional links between dietary fiber, intestinal microbiota, and obesity phenotype are still not fully understood. Combined soluble fiber (CSF) is a synthetic mixture of polysaccharides and displays high viscosity, water-binding capacity, swelling capacity, and fermentability. We found that supplementing high-fat diet (HFD) with 6% CSF significantly improved the insulin sensitivity of obese mice without affecting their body weight. Replacing the HFD with normal chow basal diet (NCD), the presence of CSF in the feed significantly enhanced satiety, decreased energy intake, promoted weight and fat loss, and augmented insulin sensitivity. CSF also improved the intestinal morphological integrity, attenuated systemic inflammation, promoted intestinal microbiota homeostasis, and stabilized the production of short-chain fatty acids (SCFAs) that was perturbed during HFD-induced obesity, and these stabilizing effects were more prominent when the basal diet was switched to NCD. The enrichment of bacteria of the S24-7 family and Allobaculum genus increased markedly in the intestine following 6% CSF supplementation- and correlated with decreased adiposity and insulin resistance. Five bacterial genera that were decreased by CSF, including Oscillospira, unclassified Lachonospitaceae, unclassified Clostridiales, unclassified Desulfovibrionaceae, and unclassified Ruminococcae, were subjected to co-occurrence network analysis and were positively correlated to adiposity and insulin resistance, indicating a key role in the microbial response to CSF. Thus, CSF has a potential to promote insulin sensitivity and even reduce obesity via beneficial regulation of the gut microecosystem.
| S-EPMC7071167 | biostudies-literature
Project description:We measured the effect of an aerobic exercise session on postprandial glucose control in adolescents with habitually low-physical activity. The goal was to determine if the acute or residual response of exercise was altered in people who are overweight/obese (OW/Ob). Eleven normal weight, body mass index (NW, BMI =?48?±?13 percentile) and 12 OW/Ob (BMI =?91?± 5 percentile) participants completed 3 trials. In the no exercise (No Ex) trial, participants rested quietly before and after consuming a test meal. In the other 2 trials, a 45-minute aerobic exercise session was performed either 17-hour (Prior Day Ex) or 40 minutes (Same Day Ex) before the test meal. On all trials, the OW/Ob group had higher fasting glucose (~6%) and insulin (~66%), and lower insulin sensitivity (~9%) than the NW group. The Same Day Ex and Prior Day Ex trials resulted in reduced area under the curve for glucose (6% on both trials, P <?.01) and insulin (15% and 13%, respectively, P <?.03), and increased insulin sensitivity (8% and 6%, respectively, P <?.01). The magnitudes of those effects did not differ between the NW and OW/Ob groups. Plasma fatty acids declined and carbohydrate oxidation increased after the meal, but did not differ among trials or groups. The results demonstrate that moderate intensity aerobic exercise increases insulin sensitivity in NW and OW/Ob adolescents and that the beneficial effects of exercise last up to 17?hours. The acute impact of exercise on metabolic health in adolescents is not impaired in overweight/obese participants.
| S-EPMC6201285 | biostudies-literature
Project description:Berries and other anthocyanin-rich treatments have prevented weight gain and adiposity in rodent models of diet-induced obesity. Their efficacy may be explained by modulation of energy substrate utilization. However, this effect has never been translated to humans. The objective of this study was to evaluate the effects of berry intake on energy substrate use and glucoregulation in volunteers consuming a high-fat diet. Twenty-seven overweight or obese men were enrolled in a randomized, placebo-controlled crossover study with two treatment periods. Subjects were fed an investigator controlled, high-fat (40% of energy from fat) diet which contained either 600 g/day blackberries (BB, 1500 mg/day flavonoids) or a calorie and carbohydrate matched amount of gelatin (GEL, flavonoid-free control) for seven days prior to a meal-based glucose tolerance test (MTT) in combination with a 24 h stay in a room-sized indirect calorimeter. The washout period that separated the treatment periods was also seven days. The BB treatment resulted in a significant reduction in average 24 h respiratory quotient (RQ) (0.810 vs. 0.817, BB vs. GEL, p = 0.040), indicating increased fat oxidation. RQ during the MTT was significantly lower with the BB treatment (0.84) compared to GEL control (0.85), p = 0.004. A 4 h time isolation during dinner showed similar treatment effects, where RQ was reduced and fat oxidation increased with BB (0.818 vs. 0.836, 28 vs. 25 g, respectively; BB vs. GEL treatments). The glucose AUC was not different between the BB and GEL treatments during the MTT (3488 vs. 4070 mg·min/dL, respectively, p = 0.12). However, the insulin AUC was significantly lower with the BB compared to the GEL control (6485 vs. 8245 µU·min/mL, p = 0.0002), and HOMA-IR improved with BB (p = 0.0318). Blackberry consumption may promote increased fat oxidation and improved insulin sensitivity in overweight or obese males fed a high fat diet.
| S-EPMC6115824 | biostudies-literature
Project description:This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (S(I)) in participants with waist circumference ?89 (women) or ?102 cm (men). Participants received 0 (control starch), 15, or 30 g/d (double-blind) of HAM-RS2 in random order for 4-wk periods separated by 3-wk washouts. Minimal model S(I) was assessed at the end of each period using the insulin-modified i.v. glucose tolerance test. The efficacy evaluable sample included 11 men and 22 women (mean ± SEM) age 49.5 ± 1.6 y, with a BMI of 30.6 ± 0.5 kg/m2 and waist circumference 105.3 ± 1.3 cm. A treatment main effect (P = 0.018) and a treatment × sex interaction (P = 0.033) were present. In men, least squares geometric mean analysis for S(I) did not differ after intake of 15 g/d HAM-RS2 (6.90 × 10?? pmol?¹ · L?¹ × min?¹) and 30 g/d HAM-RS2 (7.13 × 10?? pmol?¹ · L?¹ × min?¹), but both were higher than after the control treatment (4.66 × 10?? pmol?¹ · L?¹ × min?¹) (P < 0.05). In women, there was no difference among the treatments (overall least squares ln-transformed mean ± pooled SEM = 1.80 ± 0.08; geometric mean = 6.05 × 10?? pmol?¹ · L?¹ × min?¹). These results suggest that consumption of 15-30 g/d of HAM-RS2 improves S(I) in men. Additional research is needed to understand the mechanisms that might account for the treatment × sex interaction observed.
| S-EPMC3301990 | biostudies-literature
Project description:OBJECTIVE:To test the hypothesis that insulin secretion and insulin sensitivity would be improved in adolescents after Roux-en-Y gastric bypass (RYGB). STUDY DESIGN:A longitudinal study of 22 adolescents and young adults without diabetes undergoing laparoscopic RYGB (mean age 17.1 ± 1.42 years; range 14.5-20.1; male/female 8/14; Non-Hispanic White/African American 17/5) was conducted. Intravenous glucose tolerance tests were done to obtain insulin sensitivity (insulin sensitivity index), insulin secretion (acute insulin response to glucose ), and the disposition index as primary outcome variables. These variables were compared over the 1 year of observation using linear mixed modeling. RESULTS:In the 1-year following surgery, body mass index fell by 38% from a mean of 61 ± 12.3 to 39 ± 8.0 kg/m(2) (P < .01). Over the year following surgery, fasting glucose and insulin values declined by 54% and 63%, respectively. Insulin sensitivity index increased 300% (P < .01), acute insulin response to glucose decreased 56% (P < .01), leading to a nearly 2-fold increase in the disposition index (P < .01). Consistent with improved ?-cell function, the proinsulin to C-peptide ratio decreased by 21% (P < .01). CONCLUSIONS:RYGB reduced body mass index and improved both insulin sensitivity and ?-cell function in severely obese teens and young adults. These findings demonstrate that RYGB is associated with marked metabolic improvements in obese young people even as significant obesity persists. TRIAL REGISTRATION:ClinicalTrials.gov: NCT00360373.
| S-EPMC4843108 | biostudies-literature
Project description:ContextThe exact mechanisms responsible for increased plasma triglyceride (TG) concentration in obese people are unclear, and it is not known whether excess energy intake per se is involved in the pathophysiology of this abnormality.ObjectiveThe purpose of our study was to examine how excess energy intake from a balanced diet for 1 day affects very-low-density lipoprotein (VLDL)-TG kinetics and its putative regulators hepatic insulin sensitivity and plasma free fatty acid availability.Subjects and designWe used stable isotope-labeled tracer methods to evaluate glucose and lipid kinetics in 8 overweight and obese men (age, 38 ± 3 years; body mass index, 33.7 ± 1.7 kg/m(2); means ± SEM) on 2 occasions (randomized crossover design): once, the day after they consumed a balanced diet that provided an amount of energy that matched their energy expenditure, and another time, the day after they consumed a balanced diet that provided 30% excess calories. Eight healthy, lean men (34 ± 1 years; 22.5 ± 0.6 kg/m(2)) were studied under isocaloric conditions only to provide a reference for normal lipid kinetics.ResultsVLDL-TG and VLDL-apolipoprotein B-100 (apoB-100) concentrations and secretion rates were significantly greater (P < .01) in overweight/obese compared with lean men. Hypercaloric, compared with isocaloric, feeding in overweight/obese men increased glucose rate of appearance in plasma (904 ± 21 vs 873 ± 26 μmol/min), the hepatic insulin resistance index (10.9 ± 2.2 vs 8.3 ± 1.8), and VLDL-apoB-100 concentration and secretion rate (1.91 ± 0.24 vs. 1.53 ± 0.13 nmol/min), whereas VLDL-apoB-100 plasma clearance rate, VLDL-TG secretion and plasma clearance rates, and free fatty acid rate of appearance in plasma were not affected by overfeeding.ConclusionOne day of moderate overfeeding (30% excess energy intake) stimulates hepatic glucose and VLDL-apo B-100 secretion rates but has no effect on hepatic and adipose tissue fatty acid metabolism in overweight/obese men.
| S-EPMC3733854 | biostudies-literature
Project description:ObjectiveGinseng and its active component, ginsenoside Re, are popular herbal products that are advocated for treatment of diabetes. The purpose of this study was to determine whether ginseng or ginsenoside Re improves β-cell function and insulin sensitivity (IS) in insulin-resistant subjects.Research design and methodsOverweight or obese subjects (BMI = 34 ± 1 kg/m²) with impaired glucose tolerance or newly diagnosed type 2 diabetes were randomized to 30 days of treatment with ginseng root extract (8 g/day), ginsenoside Re (250-500 mg/day), or placebo. β-Cell function was assessed as the disposition index (DI) and measured by a frequently sampled oral glucose tolerance test, and IS was assessed as the relative increase in glucose disposal during a hyperinsulinemic-euglycemic clamp procedure plus stable isotope tracer infusion.ResultsValues for DI and IS after therapy (Post) were not different from values before therapy (Pre) in the placebo (DI: Pre, 5.8 ± 0.9 × 10⁻³ and Post, 5.8 ± 0.8 × 10⁻³, P = 0.99; IS: Pre,165 ± 29% and Post, 185 ± 24%, P = 0.34), ginseng (DI: Pre, 7.7 ± 2.0 × 10⁻³ and Post, 6.0 ± 0.8 × 10⁻³, P = 0.29; IS: Pre, 171 ± 72% and Post,137 ± 59%, P = 0.88), and ginsenoside Re (DI: Pre, 7.4 ± 3.0 × 10⁻³ and Post, 5.9 ± 1.1 × 10⁻³, P = 0.50; IS: Pre, 117 ± 31% and Post, 134 ± 34%, P = 0.44) groups. Ginsenosides Re, Rb₁, and Rb₂ were not detectable in plasma after treatment with ginseng root extract or ginsenoside Re.ConclusionsOral ginseng or ginsenoside Re therapy does not improve β-cell function or IS in overweight/obese subjects with impaired glucose tolerance or newly diagnosed diabetes. Poor systemic bioavailability might be responsible for the absence of a therapeutic effect.
| S-EPMC3114517 | biostudies-literature
Project description:AIMS/HYPOTHESIS:Insulin resistance in skeletal muscle and liver plays a major role in the pathophysiology of type 2 diabetes. The hyperinsulinaemic-euglycaemic clamp is considered the gold standard for assessing peripheral and hepatic insulin sensitivity, yet it is a costly and labour-intensive procedure. Therefore, easy-to-measure, cost-effective approaches to determine insulin sensitivity are needed to enable organ-specific interventions. Recently, evidence emerged that plasma cathepsin D (CTSD) is associated with insulin sensitivity and hepatic inflammation. Here, we aimed to investigate whether plasma CTSD is associated with hepatic and/or peripheral insulin sensitivity in humans. METHODS:As part of two large clinical trials (one designed to investigate the effects of antibiotics, and the other to investigate polyphenol supplementation, on insulin sensitivity), 94 overweight and obese adults (BMI 25-35 kg/m2) previously underwent a two-step hyperinsulinaemic-euglycaemic clamp (using [6,6-2H2]glucose) to assess hepatic and peripheral insulin sensitivity (per cent suppression of endogenous glucose output during the low-insulin-infusion step, and the rate of glucose disappearance during high-insulin infusion [40 mU/(m2 × min)], respectively). In this secondary analysis, plasma CTSD levels, CTSD activity and plasma inflammatory cytokines were measured. RESULTS:Plasma CTSD levels were positively associated with the proinflammatory cytokines IL-8 and TNF-? (IL-8: standardised ? = 0.495, p < 0.001; TNF-?: standardised ? = 0.264, p = 0.012). Plasma CTSD activity was negatively associated with hepatic insulin sensitivity (standardised ? = -0.206, p = 0.043), independent of age, sex, BMI and waist circumference, but it was not associated with peripheral insulin sensitivity. However, plasma IL-8 and TNF-? were not significantly correlated with hepatic insulin sensitivity. CONCLUSIONS/INTERPRETATION:We demonstrate that plasma CTSD activity, but not systemic inflammation, is inversely related to hepatic insulin sensitivity, suggesting that plasma CTSD activity may be used as a non-invasive marker for hepatic insulin sensitivity in humans.
| S-EPMC6946744 | biostudies-literature